For the sake of argument, however, let us assume that the sociobiologists are absolutely right in their idea that all aspects of human nature (as it were) are at least partially genetically determined. Let us assume, furthermore, that the genes governing these aspects are identified and located in the human genome. Then, just like physical characteristics and mental abilities, they can eventually be selected for (or against) on a permanent basis. What would a society with an excess of altruists (or no altruists at all) be like? If there are no longer any threats from lethal or semi-lethal genes, would there be any need for an incest taboo (either societally or genetically determined)?
To take a less obvious example, what would the world be like if everyone were non-aggressive? How would this affect the nature of our society or, equally important, the ways in which other aspects of our humanness are expressed? What relationship might there be between aggression and ambition? Between aggression and creativity? Between aggression and sexual response? What would happen if, instead of 100% non-aggressive individuals, there were 99.9% non-aggressives and 0.1% aggressives?
The nature/ nurture controversy has been with us for many years, with different schools of behavior assigning different weighting factors to the two halves. Lewontin and coworkers have suggested that, whatever view one takes on this issue, it becomes a fundamentally reductionist and deterministic description of human potential. Their own view is that the development process is a dynamic and synergistic relationship where, in effect, the whole is greater than the sum of its parts. However, whether one agrees with Lewontin or takes a more usual stance, there is no question but that changes in the distribution of even simple physical traits can change society and individuals growing up in that society in ways that we have not really thought about, as shown in the previous discussion of increased longevity.
If we extend the discussion of the nature of humanness to include, not only physical traits but also manual skills and intellectual gifts, it is clear that skewing the human range of potential through genetic manipulation will have unforeseen and perhaps unimaginable effects. And by adding into consideration the possibility that, as the sociobiologists contend, ALL aspects of “human nature” are genetically determined (at least in part), we are faced with a situation where we are capable of altering ourselves completely as a species. The augmentation of human capabilities, either physical, mental, or emotional, outside the current human range is equally possible, but does not even have to be considered seriously at this point, since the promise and threat to ourselves within the human range of possibility is itself awesome.